Is infertility a genetic issue or environmental?

I’m curious because I started TTC 3 months ago with no luck yet. I’m 24 if that matters. It seems so hard and I noticed it’s a common issue on Glow.

Nobody from both sides of my family had issues. My mom had her first baby at 30 (took 4 months of trying) and then had an oopsie (or surprise) at 33. My grandma- moms mother had 3 kids back to back from ages 23-26 with no issues. My grandma, dads side had 4 kids back to back, starting at 28-33 (which was old back in the 50s). My aunt, dads sister had 2 kids in her 30s and third one at 43. So it doesn’t seem my family had issues but for some reason I feel like I will not be able to easily or naturally. My family thinks I’m too young because they all started older but they don’t understand how it’s harder to conceive these days. I wonder if it’s from the food we eat or stress. What could it be? I’m feeling doubtful and depressed